Realization of filter-free fluorescence image sensor

In this study, we developed a filter-free fluorescence image sensor that performed 2D fluorescence imaging without optical filters utilizing the wavelength-dependent absorption depth of a silicon substrate. This sensor changes the potential distribution in the depth direction of the silicon substrate by controlling a potential of the polysilicon gate atop the sensing area. And it can display both images of excitation light and fluorescence at the same time by measuring each light absorption current. We obtained a 2D image of quantum dot emission immobilized on the 32 × 32 filter-free fluorescence image sensor. Quantum dot emitted light with a wavelength of 620 nm by excitation light with a wavelength of 470nm. The proposed image sensor can measure and display 2D images of more than two kinds of light wavelengths at the same time by controlling the photogate voltage.